To avoid social desirability responding, we apply the Implicit Association Tests (IAT) technique (Greenwald, McGhee, & Schwartz, 1998; Banaji, 2001) to measure students’ implicit attitudes toward low carbon behavior attitude. A new IAT instrument was developed and the results compared with the self-report Explicit Behavior Attitude (EBA) questionnaire for exploring the validity of IAT. We find the IAT does have more advantages in validity and reliability (Cronbach’s Alpha=.92), and effective in measuring the implicit attitudes on low carbon behavior attitude to avoid social desirability responding.